EP3460352A1 - Boiler - Google Patents

Boiler Download PDF

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Publication number
EP3460352A1
EP3460352A1 EP18194990.0A EP18194990A EP3460352A1 EP 3460352 A1 EP3460352 A1 EP 3460352A1 EP 18194990 A EP18194990 A EP 18194990A EP 3460352 A1 EP3460352 A1 EP 3460352A1
Authority
EP
European Patent Office
Prior art keywords
combustion
supply duct
chamber
combustion chamber
gas
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP18194990.0A
Other languages
German (de)
English (en)
French (fr)
Inventor
Giovanni Pisani
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ICI Caldaie SpA
Original Assignee
ICI Caldaie SpA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by ICI Caldaie SpA filed Critical ICI Caldaie SpA
Publication of EP3460352A1 publication Critical patent/EP3460352A1/en
Pending legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H1/00—Water heaters, e.g. boilers, continuous-flow heaters or water-storage heaters
    • F24H1/18—Water-storage heaters
    • F24H1/186—Water-storage heaters using fluid fuel
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23D—BURNERS
    • F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
    • F23D14/02—Premix gas burners, i.e. in which gaseous fuel is mixed with combustion air upstream of the combustion zone
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23D—BURNERS
    • F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
    • F23D14/46—Details, e.g. noise reduction means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23D—BURNERS
    • F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
    • F23D14/46—Details, e.g. noise reduction means
    • F23D14/62—Mixing devices; Mixing tubes
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23L—SUPPLYING AIR OR NON-COMBUSTIBLE LIQUIDS OR GASES TO COMBUSTION APPARATUS IN GENERAL ; VALVES OR DAMPERS SPECIALLY ADAPTED FOR CONTROLLING AIR SUPPLY OR DRAUGHT IN COMBUSTION APPARATUS; INDUCING DRAUGHT IN COMBUSTION APPARATUS; TOPS FOR CHIMNEYS OR VENTILATING SHAFTS; TERMINALS FOR FLUES
    • F23L17/00—Inducing draught; Tops for chimneys or ventilating shafts; Terminals for flues
    • F23L17/005—Inducing draught; Tops for chimneys or ventilating shafts; Terminals for flues using fans
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23L—SUPPLYING AIR OR NON-COMBUSTIBLE LIQUIDS OR GASES TO COMBUSTION APPARATUS IN GENERAL ; VALVES OR DAMPERS SPECIALLY ADAPTED FOR CONTROLLING AIR SUPPLY OR DRAUGHT IN COMBUSTION APPARATUS; INDUCING DRAUGHT IN COMBUSTION APPARATUS; TOPS FOR CHIMNEYS OR VENTILATING SHAFTS; TERMINALS FOR FLUES
    • F23L5/00—Blast-producing apparatus before the fire
    • F23L5/02—Arrangements of fans or blowers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23N—REGULATING OR CONTROLLING COMBUSTION
    • F23N3/00—Regulating air supply or draught
    • F23N3/005—Regulating air supply or draught using electrical or electromechanical means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H1/00—Water heaters, e.g. boilers, continuous-flow heaters or water-storage heaters
    • F24H1/18—Water-storage heaters
    • F24H1/20—Water-storage heaters with immersed heating elements, e.g. electric elements or furnace tubes
    • F24H1/205—Water-storage heaters with immersed heating elements, e.g. electric elements or furnace tubes with furnace tubes
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H1/00—Water heaters, e.g. boilers, continuous-flow heaters or water-storage heaters
    • F24H1/22—Water heaters other than continuous-flow or water-storage heaters, e.g. water heaters for central heating
    • F24H1/24—Water heaters other than continuous-flow or water-storage heaters, e.g. water heaters for central heating with water mantle surrounding the combustion chamber or chambers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H1/00—Water heaters, e.g. boilers, continuous-flow heaters or water-storage heaters
    • F24H1/22—Water heaters other than continuous-flow or water-storage heaters, e.g. water heaters for central heating
    • F24H1/24—Water heaters other than continuous-flow or water-storage heaters, e.g. water heaters for central heating with water mantle surrounding the combustion chamber or chambers
    • F24H1/26—Water heaters other than continuous-flow or water-storage heaters, e.g. water heaters for central heating with water mantle surrounding the combustion chamber or chambers the water mantle forming an integral body
    • F24H1/28—Water heaters other than continuous-flow or water-storage heaters, e.g. water heaters for central heating with water mantle surrounding the combustion chamber or chambers the water mantle forming an integral body including one or more furnace or fire tubes
    • F24H1/285—Water heaters other than continuous-flow or water-storage heaters, e.g. water heaters for central heating with water mantle surrounding the combustion chamber or chambers the water mantle forming an integral body including one or more furnace or fire tubes with the fire tubes arranged alongside the combustion chamber

Definitions

  • the present invention relates to a boiler.
  • Boilers are known for the production of hot water or steam which are constituted by an external enclosure which forms a water heating chamber and accommodates internally a firebox, which is in a heat exchange relationship with the water to be heated that is contained in the heating chamber.
  • a combustion chamber is formed in the firebox and accommodates the combustion head of a burner capable of generating a flame in the firebox.
  • the combustion chamber is connected to a plurality of heat exchange tubes in which the hot combustion gases produced by the flame flow and pass through the heating chamber, so that the hot combustion gases can heat the water contained in the heating chamber.
  • the heat exchange tubes merge in a combustion gas collection chamber, from which they are evacuated externally through a stack.
  • the burner used in the boilers as described above can be of the forced draft type, also known as jet burner or draft burner, in which a fan, arranged outside the boiler and upstream of the burner, propels by forcing the oxidizing air, drawn from the outside environment, toward the burner.
  • a fan arranged outside the boiler and upstream of the burner, propels by forcing the oxidizing air, drawn from the outside environment, toward the burner.
  • premixed gas burners normally termed premix burners, in which the combustible gas and the oxidizing air are fully mixed, prior to their combustion reaction, which occurs in the combustion head, by a premixer which is connected to the combustion head by means of a fan, without requiring any secondary air to complete the combustion of the mixture of air and gas.
  • One problem of known burners is providing optimum combustion of the mixture formed by oxidizing air and by the combustible gas in order to reduce the forming of NOx that are subsequently sent to the stack of the boiler.
  • the total NOx detectable at the stack are constituted mainly by thermal NOx, the generation of which increases with the temperature of the flame in which molecules of nitrogen and oxygen occur which do not take part directly in the combustion and which can originate to a lesser extent also from so-called prompt NOx, which depend on the stoichiometry of the combustion process, and from so-called fuel NOx, which form due to the nitrogen that is present in the fuel.
  • combustion gas recirculation In burners of the forced draft type, combustion gas recirculation must be adjusted with a valve with automatic adjustment which allows an opening thereof which is variable on the basis of the parameters of the combustion and on flame power, and therefore a combustion gas temperature probe is necessary, an oxygen probe is often necessary, and in any case the presence is also required of an electronic device that modulates the opening of the valve, with consequent constructive complications.
  • the aim of the present invention is to provide a boiler that is capable of improving the background art in one or more of the aspects indicated above.
  • an object of the invention is to provide a boiler that is capable of ensuring a reduced emission of NOx without requiring particular structural and constructive complications and without reductions in efficiency.
  • Another object of the invention is to provide a boiler which, by virtue of its particular constructive characteristics, is capable of giving the greatest assurances of reliability and safety in its operation.
  • a further object of the present invention is to provide a boiler that is easy to manage and does not require specific electronic combustion control systems.
  • Another object of the invention is to provide a boiler that does not required the use of automatically adjusted valves to control NOx emission.
  • a further object of the present invention is to overcome the drawbacks of the background art in a manner that is alternative to any existing solutions.
  • Another object of the invention is to provide a boiler that is relatively easy to provide and can be obtained at competitive costs.
  • the boiler according to the invention designated generally by the reference numeral 1, comprises an enclosure 2, which forms a heating chamber 3, in which the water to be heated is contained.
  • the enclosure 2 and other components of the boiler are contained in an external box-like protection and thermal insulation structure 1a.
  • the enclosure 2 accommodates a firebox 4 which forms a combustion chamber 5, with which a burner 6 is associated.
  • the burner 6 comprises a combustion head 7, which is arranged in the combustion chamber 5 and is connected to a supply duct 8 and is provided with a premixer 9 of oxidizing air and combustible gas which is interposed along the supply duct 8, so that it can perform a premixing of the air and of the gas fed to the combustion head 7.
  • the combustion chamber 5 is connected to a plurality of tubes 10 for conveying the combustion gases which are arranged in a heat exchange relationship with the heating chamber 3, so that the combustion gases can transfer heat to the water contained in the heating chamber 3.
  • the conveyance tubes 10 lead into a combustion gas collection chamber 11, which is connected to a stack 12 for the evacuation of the combustion gases into the outside environment.
  • Means are further provided for generating the flow of a mixture formed by oxidizing air and combustible gas toward the combustion head 7, so that the combustion head 7 can create and maintain a flame inside the combustion chamber 5.
  • the boiler according to the invention comprises at least one duct 13 for conveying the combustion gases, which connects the stack 12 to the supply duct 8 of the burner 6, and in that said flow generation means comprises means adapted to place the combustion chamber 5 in partial vacuum with respect to atmospheric pressure.
  • said means adapted to place the combustion chamber 5 in partial vacuum are provided by a fan 14 which is arranged in the combustion gas collection chamber 11 and can be rotationally actuated by a motor 14a.
  • the combustion gas conveyance duct 13 can be connected to the supply duct 8 of the burner 6 in any point downstream of the premixer 9 along the direction of the flow that passes through the supply duct 8.
  • the supply duct 8 is advantageously connected in input to the outside environment, so as to be supplied with oxidizing air, while the premixer 9 is provided by means of a tubular element 15, which is arranged coaxially to the supply duct 8, so as to create a reduction in the cross-section of the supply duct itself.
  • tubular element 9 is conveniently provided, at its end directed against the flow that arrives from the supply duct 8, with a portion 15a which is substantially shaped like an ogive and is internally connected to a gas supply duct 16.
  • the fan 14 is activated so as to create a partial vacuum with respect to the outside environment in the combustion chamber 5 and consequently generate a flow of air, drawn from the outside environment, through the supply duct 8 of the burner 6.
  • the air flow in the supply duct 8 by passing through the region in which the tubular element 15 is located, draws by Venturi effect the gas that arrives from the supply duct through the openings 17 of the tubular element 15, so as to create in the supply duct 8 a mixture of air and combustible gas which allows the combustion head 7 to generate a flame in the combustion chamber 5.
  • the combustion gases that originate from the flame generated in the combustion chamber 5 by the combustion head are channeled into the conveyance tubes 10, exchange heat with the water contained in the heating chamber 3, and gather, by now depleted, in the combustion gas collection chamber 11, where the fan 14 propels them into the stack 12.
  • At least part of the combustion gases that flow within the stack 12 are channeled along the conveyance duct 13 to thus reach the supply duct 8, where they mix with the air and the gas that are fed to the combustion head 7, thus creating a recirculation of the combustion gases inside the boiler which are sent to the burner 6.
  • the quantity of recirculation combustion gases that is recirculated through the conveyance duct 13 can optionally be adjusted, at the first ignition of the burner 6, with a manual shutter which is then permanently locked, in order to maintain the achieved optimization of the main combustion parameters, which are constituted by the percentage of oxygen, by the quantity of carbon monoxide (CO) in ppm and by the quantity of NOx in the combustion gases in ppm.
  • the main combustion parameters which are constituted by the percentage of oxygen, by the quantity of carbon monoxide (CO) in ppm and by the quantity of NOx in the combustion gases in ppm.
  • the variation of the speed of the fan 14 produces a simultaneous variation of combustion air, combustible gas and combustion gases that recirculate in the conveyance duct 13 without requiring any intervention to vary the adjustment performed previously on the manual shutter. This is demonstrated by the fact that the combustion parameters do not undergo substantial variations over the entire modulation range of the burner 6 even if the temperature of the boiler varies.
  • combustion chamber 5 is in partial vacuum ensures that there are no unwanted leaks of the depleted combustion gases from the conveyance duct.
  • the invention achieves the intended aim and objects, providing a boiler that is capable of ensuring a low emission of NOx without deteriorations in the efficiency of the boiler.
  • the materials used may be any according to the requirements and the state of the art.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
EP18194990.0A 2017-09-25 2018-09-18 Boiler Pending EP3460352A1 (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
IT102017000106691A IT201700106691A1 (it) 2017-09-25 2017-09-25 Caldaia.

Publications (1)

Publication Number Publication Date
EP3460352A1 true EP3460352A1 (en) 2019-03-27

Family

ID=61006232

Family Applications (1)

Application Number Title Priority Date Filing Date
EP18194990.0A Pending EP3460352A1 (en) 2017-09-25 2018-09-18 Boiler

Country Status (4)

Country Link
US (1) US20190093922A1 (it)
EP (1) EP3460352A1 (it)
CN (1) CN109556111A (it)
IT (1) IT201700106691A1 (it)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114111030A (zh) * 2021-11-15 2022-03-01 巨鹿县申源建材有限公司 商品混凝土冬季用水快速加温设备

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2314448A1 (fr) * 1975-06-09 1977-01-07 Vidalenq Maurice Chaudiere a gaz, notamment pour le chauffage central
US4204832A (en) * 1978-08-10 1980-05-27 Modine Manufacturing Company Gas burner device
US4993402A (en) * 1989-12-18 1991-02-19 Carrier Corporation Fuel efficient rapid response water heating module
EP1052461A2 (en) * 1999-05-12 2000-11-15 State Industries, Inc. Water heater

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3437322A (en) * 1966-06-21 1969-04-08 John H Flynn Air-heating gas burner
US3419339A (en) * 1967-02-08 1968-12-31 Hauck Mfg Co Inspirator assembly
CN1017744B (zh) * 1988-12-26 1992-08-05 株式会社日立制作所 低氮氧化物锅炉
US5195883A (en) * 1992-04-01 1993-03-23 Aqua-Chem, Inc. Flue gas recirculation system with fresh air purge for burners
IT1256091B (it) * 1992-11-02 1995-11-27 Enrico Sebastiani Apparecchio per la combustione di gas con un bruciatore atmosferico e metodo per la sua alimentazione
TW278124B (it) * 1994-10-14 1996-06-11 Toyota Motor Co Ltd
JP4635636B2 (ja) * 2005-02-10 2011-02-23 三浦工業株式会社 ボイラおよび低ＮＯｘ燃焼方法
WO2011034999A1 (en) * 2009-09-16 2011-03-24 Heat Solutions, Inc. Fluid heater
CN103884101A (zh) * 2012-12-24 2014-06-25 苗苏宁 板式燃气燃烧冷凝式热水锅炉
EP3093579A1 (en) * 2015-05-12 2016-11-16 I.C.I. CALDAIE S.p.A. Condensing boiler
CN205717174U (zh) * 2016-03-09 2016-11-23 浙江尚鼎工业炉有限公司 一种燃气加热炉

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2314448A1 (fr) * 1975-06-09 1977-01-07 Vidalenq Maurice Chaudiere a gaz, notamment pour le chauffage central
US4204832A (en) * 1978-08-10 1980-05-27 Modine Manufacturing Company Gas burner device
US4993402A (en) * 1989-12-18 1991-02-19 Carrier Corporation Fuel efficient rapid response water heating module
EP1052461A2 (en) * 1999-05-12 2000-11-15 State Industries, Inc. Water heater

Also Published As

Publication number Publication date
CN109556111A (zh) 2019-04-02
US20190093922A1 (en) 2019-03-28
IT201700106691A1 (it) 2019-03-25

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